Storage devices are used in the vast majority of semiconductor integrated circuits. In many of these integrated circuits a need exists for the storage devices to be non-volatile meaning that stored data remains even when electrical power is removed from the integrated circuit. Typically, non-volatile storage devices require additional processing complexity to form non-volatile storage devices. For example, multiple layers of material such as polysilicon are required to implement a floating gate transistor which is a common transistor used to implement a nonvolatile storage device. Additionally, the programming and erasing of these devices is complex wherein multiple voltages at possibly different polarities are required. Another characteristic of many non-volatile storage devices is an undesirably large power consumption which is required to store the data in a non-volatile element. Further, a complex reference circuit is required to reliably sense the state of a non-volatile storage device. These characteristics of existing non-volatile storage devices create circuits which are either complex and therefore more costly to manufacture, which have significant power consumption, and/or which require significant circuit area.
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